In conventional control system for fuel injection into an internal combustion engine, when a solenoid valve of an injector is opened, a battery voltage VB is boosted with a boosting circuit and then a high voltage that has thus been generated by the boosting circuit is applied to the injector for accelerated response of the solenoid valve in the injector. In this conventional technique, a capacitor, for example, is used as an element for storage of the boosted electrical charge.
When the control system opens the solenoid valve of the injector, since the system consumes the charge energy and lowers the voltage, a recharge of the capacitor from the boosting circuit is started. During the recharge, if next injection timing precedes storage of a sufficient amount of charge energy for valve opening of the injector, the valve of the injector can by no means be opened or even if the valve can be opened, the injector may malfunction. These events have caused variations in fuel injection accuracy of the injector.
In order to solve this problem, providing a plurality of energy storage capacitors and boosting circuits and using both in alternate form, for example, is proposed as described in Patent Documents 1 and 2.